The present invention is related to an electric vacuum cleaner.
A general electric vacuum cleaner is so constructed to take in dirty air through a floor nozzle, introduce it into the body of the vacuum cleaner, clean the air through a dust collector in the vacuum cleaner, and exhaust the cleaned air to the outside of vacuum cleaner. The dust collector captures dust by filtration using a paper filter or by centrifugal separation using a cylindrical separation cyclone to clean the air.
Japanese Application Patent Laid-Open Publication 2001-29288 discloses an electric vacuum cleaner with a cyclonic separation type dust collector. The dust collector in the electric vacuum cleaner is so constructed that one cyclonic separation cylinder may capture dust in dirty air by centrifugal separation.
Published Japanese translations of PCT international publication for patent applications 10-511880 discloses, as a cyclonic separation dust collector in an electric vacuum cleaner, a dust separator having a cyclonic separation type dust collector comprising outer and inner separation cylinders in which the outer separation cylinder centrifugally removes relatively large particles and the inner separation cylinder centrifugally removes fine particles.
For general home electric vacuum cleaners, it is most important that they are compact and convenient in handling. Further, their dust collector must be smaller and the collected dust must be disposed of easily.
The dust collector having a single cyclonic separation cylinder catches both large and fine dust particles together. This cannot prevent fine dust from being easily raised up when it is taken out from the vacuum cleaner for disposal. Further, the cyclonic separation cylinder must be longer and greater to increase the dust catching ability (or collecting and cleaning ability).
A dual-cylinder type cyclonic dust separator (dust collector) has a combination of inner and outer separation cylinders, but it is very difficult to make it compact and convenient in handling. For general home use, lots of large dust particles are captured and must be frequently taken out from the vacuum cleaner. In this dust separator configuration, it is impossible to take out only the outer cylinder that captured large dust particles for disposal.